Flooring materials based on thermoplastic resins such as polyvinyl chloride (PVC) have been used for buildings, such as houses, offices, and the like. Flooring materials formed of polyvinyl chloride have low heat resistance and thus can suffer from severe contraction when heated, for example, when used with an under-floor heating system. To prevent this problem, in general, a glass fibers sheet or glass fiber scrim may be separately prepared and stacked thereon, or additives for preventing contraction may beadded thereto. Recently, to achieve widespread application of thermoplastic resins having good processability, various attempts have been made to prevent contraction of the thermoplastic resins while securing economic feasibility and improving mechanical properties.